Rotary engines such as the ones known as Wankel engines use the eccentric rotation of a piston to convert pressure into a rotating motion, instead of using reciprocating pistons. In these engines, the rotor includes a number of apex portions which remain in contact with a peripheral wall of the rotor cavity of the engine throughout the rotational motion of the rotor through respective apex seals.
In use, the apex seals are pressed against the peripheral wall and as such may tend to penetrate the openings of peripheral intake and/or exhaust ports. As such, the apex seals may hit on downstream edges of these openings, which can lead to apex seal and/or port edge damage, which in turn may lead to increased leakage around the apex seals.